THX Ultra

I am sorry to have to admit that I have been stupidly duped into buying a THX Ultra certified preamp to use as the audio video switching center for my home theatre system!  I was stupid because I allowed myself to be too easily convinced that THX and all it stood for was above suspicion and it never occurred to me that the evil Darth Vader was there lurking in the shadows waiting to cross me!  In the early days of THX during the early 1990's, the work they did to mix film soundtracks on Laserdisc with some real thrilling deep bass was totally fantastic and I have been enjoying it for years with my vast collection of discs, so whenever I see the THX logo on a disc, I know there is no need to doubt the sound quality!  When it came to setting up my most recent system at Chester River, I clearly wanted to keep my varying collection of power amps like the Velleman K4000 and Technics SE-A5 etc, so I needed a preamp/processor, not a receiver.  It looked like choosing a high quality top of the line preamp/processor like the Marantz AV-9000 with THX Ultra to boot was a no-brainer!

Marantz AV-9000

The Marantz AV-9000 Preamp/Processor was first available in June of 1999 and I bought mine at the end of 2001 and the unit has received many good reviews like this.  This is what Marantz have to say about it:

The Marantz AV-9000 sets a new standard in home theater control center performance and flexibility. The THX Ultra certified AV-9000 includes Dolby Digital, DTS and THX post-processing and 96kHz/24-bit audio capability for total surround sound versatility. It offers a vast complement of high-end performance and convenience features that make it the ultimate control center for the most advanced home theater systems.

FEATURES:
Dolby Digital and DTS surround sound decoding, plus Dolby Pro Logic decoding and a variety of additional surround modes
THX Ultra post-processing
96kHz/24-bit D/A converters and 24-bit A/D converters for exceptional audio quality
Component video switching
Six-channel direct inputs
Gyro-Touch tuning with digital tuner section, 30-station preset memory and a station naming function
Multi-room capability with independent control of a second room audio and video system
Special version of the RC2000 Mark II Programmable Learning Remote Control included
Wide variety of additional audio and video inputs, outputs and switching facilities, including S-video and composite video switching, coaxial and optical digital inputs and outputs, and a full selection of audio inputs
Premium-quality parts and construction
Copper-shielded HDAMs (High Definition Amplifier Modules)
Fluorescent front panel display and user-friendly on-screen menu system

Hmm..,  all sounds very impressive, so after connecting up the system I gleefully settled down to listen to my new preamp/processor with my latest CD at the time which was "Trouble in Shangri-La" by Stevie Nicks, which I had been listening to over & over the whole week on various systems, so I knew how it was supposed to sound.  Trouble!  No shit!  Well there's damn well trouble now and it ain't in Shangri-La!!!  What the hell has happened to my beautiful sounding stereo system?  It sounded like there was a big block of sound just missing from the bass, as if the subwoofer wasn't even working, yet it was working for deep bass?  What has happened?  I just spent $1400 on this THX Ultra box??  As the previous system was working with the subwoofer receiving a full range signal from the Pioneer SP-700D processor, I assumed that the subwoofer crossover frequency was just set too low for my particular system/taste although my subwoofer was in fact set to provide a second order low pass Butterworth response with a corner frequency of 80Hz as shown in blue in the graph below and described in detail here.  I started to go through the menus on the Marantz AV-9000 looking for the setup for the subwoofer crossover frequency to see how it was set.  Hmm.., I have more menus on my TV and the subwoofer setting was nowhere to be found?  To my utter dismay, I later found that the THX Ultra specification requires that the subwoofer crossover frequency be set to 80Hz with a fourth order Linkwitz Riley response falling at 24dB per octave and its NOT ADJUSTABLE!!!  Ahhhh!!!!  Can someone please explain to me how some idiot sitting in an office in California (yes I'm talking about you Lucas) can dictate to me how my speakers need to be combined with active crossovers in my house to please my ears while listening to stereo music?  I'm not watching a THX movie here!!  I'm trying to listen to a CD for gods sake!!  So it appears that no matter what input or sound field the Marantz AV-9000 is set to, it must always obey the Lucas law dictated by the evil Darth Vader in order to bear the prized THX Ultra mark.  Well as far as I am concerned, you can take your THX Ultra and stick it!  No only dose it cause this problem with stereo music, it dictates that you are not allowed to alter the general bass & treble settings which you often need to for non THX films.  Also as far as I can see, the stupid echo effects that the THX Ultra processing adds, have no value what so ever and the film soundtracks sound cleanest & best with just the plain Dolby Digital or DTS setting on the Marantz AV-9000.  So at least that annoying feature can be turned off!  It's not clear to me who is most stupid of all in this case?  Marantz for building the AV-9000 to THX standards and then paying THX to certify it, or me for paying Marantz to do all this just to annoy me?    Just in case you don't know why Darth Vader is here, THX was founded in 1983 by George Lucas, the creator and producer of all the Starwars films.

The Detail of What is Missing

The red, green and blue lines on this graph are from my subwoofer design and are described in detail here.  The blue line is in fact the overall response of my subwoofer.  I added to the graph a yellow line that shows the 80Hz  fourth order Linkwitz Riley response falling at 24dB per octave as implemented in the THX defined subwoofer low pass filter of the Marantz AV-9000.  As you can see, there is a white area of sound that used to be reproduced by the subwoofer that is now cut off!  This is what I would describe as a region of mellow tones that while not deep bass, still benefit from the extra gain of the active subwoofer.  The assumption made here by THX, is that the main front speakers are assumed to be matched to the THX standard and will therefore be handling this particular area exactly.  Well I'm sorry, those THX or THX/Small speakers as they are described on the Matantz AV-9000 menu do not reproduce this area properly for stereo music.  Only very very large speakers like my JBL SVA-2100's or Technics SB-M1's can achieve this, but I want to use my Quad ESL-63 speakers for my front system because they have the best sound, and yes I know they don't have the best bass WHICH IS WHY I HAVE A SUBWOOFERRRRRRRRRRRRRR!!!!!  This and various other interesting subwoofer  issues are described here.

The solution to the problem

As by the time that I had found all this out, it was too late to return the unit to the dealer, and the only apparent way to solve this issue (apart from reverse engineering all the DSP firmware in the AV-9000) was to modify the subwoofer so that it has four line level inputs that can be mixed together from the left, right, center and subwoofer channels of the AV-9000.  This then forms a full range mono signal that I can then filter as I wish. For most ordinary people even this solution is impossible, so I can only presume that those other owners of such THX equipment either A: Have full blown THX systems that really do work (unlikely as far as I can see judging by the size of THX certified front speakers that I have seen), B: Do not know enough about their own ears to notice anything, or C: simply have less sense than money?

Other AV-9000 issues

Well as you will know by now, I am no great AV-9000 fan and there is still more trouble to come!  What else could possibly be wrong with a $1400-00 receiver that has no amplifiers?  I mean what else is there in there anyhow?  Well of course there is a load of audio, video and digital switching and of course the Digital Signal Processing systems and the microcontroller that controls the whole thing.  All this stuff works great except for one part: The setup data that stores the system settings like which digital input is associated with which device and the various speaker settings (except for the subwoofer crossover of course!) is not reliably saved in nonvolatile memory.  In other words, on random occasions (usually after a power cut) it forgets everything!  It no longer knows which input is which and all the delay and level settings for the speakers are lost!  This is utter crap!  I can literally build my own embedded systems by etching the circuit boards in the kitchen sink and make systems that have been able to save their config data for over a decade with no trouble!  When this happens, I have to sit there and go through every config menu and re-setup everything before the system will work!  The on screen menus that are provided are of a low standard and are similar to the kind of thing you would find on a Pioneer Laserdisc player more than fifteen years ago; that is simple white block graphics on a blue background and the navigation provided on the remote is nothing short of annoying! I have actually had people comment on this page asking how to get to this sub menu or that... The menus are shown at the bottom of this page. The VFD display that is mounted in the center of the front panel is of a custom design (like Pioneer often do) but does not have a proper dot matrix display for displaying text and so the different characters displayed often do not have a matching font, again this makes it look either cheap or very old!  Just look at the X in THX as shown on the display above.  A much better solution would be to use a modern generic VFD like those made by Noritake and this is what Harman Kardon do.  Also, even though you can select which digital input is used for which selected input, you can't configure what the display says for each.  As I have two CD players connected, only one of the inputs says CD, the other one I use has to say "Tape" even though it is on digital input 2.  Things like this just add to the confusion for anyone who does not know how the system is connected (everyone in the world except for me).  Last but not least is the annoyance of the rear left output never quite making contact for more than an hour with the RCA plug that is inserted there no matter how fancy and how gold plated the plug is.  One day I'll just have to take the thing out and find where the dry joint is.  Click here to see the AV-9000 service manual and find out what's inside....

Conclusion

At the end of the day, I find that I have negative, both hardware and software issues with the AV-9000 design and because of this, I will probably never buy Marantz again and therefore I can not recommend it to anyone especially as it is the most expensive item in my system apart from my Quad electrostatic speakers and my Sharp DLP projector.  Having said that, I have at least been able to get it working and as long as the configuration memory is working, the rest of the hardware is very good although there aren't enough digital inputs.  This means that I have nowhere to plug in the PCM output from my Pioneer DVL-919E laserdisc player which prevents me from playing DTS encoded laserdiscs without moving some plugs, although I only have two such discs.  If the memory fails completely, I'll have to see if I can modify it with a lithium battery backup or whatever.  One useful feature is that the bass and treble can be nudged up or down (as long as you remember to turn off that THX crap!) via the remote as can of course the volume.  My PCRemote application uses this to adjust the tone and level of each CD being played to match that of a reference CD.  This makes it easy for PCRemote to adjust the sound with only a few remote control commands while a particular CD is being loaded.  One of my fears of replacing the AV-9000 would be the loss of this feature.  On my previous Pioneer SP-700D (like an Elite SP-91D), stepping through the equalizer values was arduous even for PCRemote because of the time it took although it too did work!  I am told that the RC2000 remote control provided with the AV-9000 is one of the best there is, but I never use it as all that stuff is done by PCRemote for me in my main system.  I did try using it over at our condo, but quickly found that it could not record from the remote of my Samsung projection TV and it had very limited macro capability, so I locked it away in a draw where it belongs!  As far as I can see, buying any high end processor is always going to lead to firmware issues be it related to DSP programming or control & usability issues.  Even if you have a unit that can be upgraded via a serial port, it doesn't guarantee that the manufacturer will provide a useable upgrade for you.  For this reason I will probably keep the AV-9000 until I have time to make a processor of my own.  With chips like the Ti TAS3004 and others that have blazing performance and cost just a few bucks, it looks like that will be my next processor project!  At least the memory will never fail, I'll have a great display and I will always be able to control it how I like!  Hmm..., that AV-9000 would sure make a nice casing for the project!  Anyone want the old guts?  The current Marantz offering of today is the AV-8003 which somehow sounds like a backward step, I guess they just weren't ready for the big leap to the AV-10000!  Again, only enough digital inputs for a small system and at almost twice the cost of the AV-9000, I would expect a Pentium class embedded system with an electric-sex touch screen interface...  At least it has what looks like a proper dot matrix display and an RS232 serial port to control it saving the need to drill a whole in the back to fit an IR sender for PCRemote, but I just can't stand the thought of all the inevitable firmware issues...  Yes, that's right...  I still have the old AV-9000 running...  Only another ten years to go to get the value out of it...

Pictures & Reference